1. Field of the Invention
The present invention relates to a transflective liquid crystal display (LCD) and, more particularly, to a transflective LCD with at least three color sub-pixel regions and at least a fourth sub-pixel region in one pixel region.
2. Description of the Prior Art
Thin film transistor (TFT) liquid crystal displays (LCD) are generally classified into reflective LCDs, transmissive LCDs, and transflective LCDs. In a reflective LCD, an ambient light in front of the panel into the panel, and is reflected by a reflective layer so that users can see what the LCD displays on the screen. In a transmissive LCD, a backlight module is installed below the panel for radiating light, and the radiated light will pass through the panel so that users can see what the LCD displays on the screen. In a transflective LCD, an ambient light and a backlight module are used simultaneously as light sources to illuminate the transflective LCD.
Generally speaking, only a little light formed by the backlight module really pass through the panel. Most of it is absorbed along the way including pass through an optical film and the panel. In addition, the transmissive LCD has a low contrast ratio under the light of the daytime or higher brightness light of the ambient. To solve the problem mentioned above, the LCDs on the market often have a transflective design.
The resolution of the LCD is increased, and the pixel is made smaller, but the size of the thin film transistors in the pixel cannot be decreased due to limitations of a fabrication process. So the ratio of pixels that the thin film transistors occupy is increased, and the open ratio of the LCD is decreased. To make a transflective LCD with a high open ratio is an important issue in the LCD field.